Radio-frequency (RF) electromagnetic radiation has been used for diagnosis and imaging of body tissues. For example, PCT International Publication WO 2011/067623, which is assigned to the assignee of the present patent application and whose disclosure is incorporated herein by reference, describes diagnostic apparatus that includes an antenna, which directs RF electromagnetic waves into a living body and generates signals responsively to the waves that are scattered from within the body. The signals are processed so as to locate a feature in a blood vessel in the body.
As another example, U.S. Patent Application Publication 2011/0130800, which is assigned to the assignee of the present patent application and whose disclosure is incorporated herein by reference, describes diagnostic apparatus, which includes a plurality of antennas, which are configured to be disposed at different, respective locations on the thorax of a living body. The antennas direct radio frequency (RF) electromagnetic waves from different, respective directions toward the heart in the body and output RF signals responsively to the waves that are scattered from the heart. The RF signals are processed over time so as to provide a multi-dimensional measurement of a movement of the heart.
U.S. Patent Application Publication 2010/0256462 describes a method for monitoring thoracic tissue fluid content by intercepting reflections of electromagnetic (EM) radiation reflected from thoracic tissue of a patient in radiation sessions during a period of at least 24 hours. A change of a dielectric coefficient of the thoracic tissue is detected by analyzing the reflections. PCT International Publication WO 2009/031149 describes a wearable monitoring apparatus comprising at least one transducer configured for delivering EM radiation to internal tissue and intercepting at least one reflection of the EM radiation therefrom. A housing for containing the transducer, along with a reporting unit and a processing unit, is configured to be disposed on the body of an ambulatory user.
The citation of certain references above is intended to provide a general overview of the state of the art and does not constitute an admission that any of the references should be considered prior art against the present patent application.